1. Field of the Invention
The present invention relates to aftermarket customization of automobile or other internal combustion engines in order to increase control, power output and efficiency of the engine while maintaining or improving the aesthetic appearance of the engine mechanics. More particularly, the present invention relates to a system for converting the fuel/air supply system of an internal combustion engine from a carbureted system to a fuel injector system while simultaneously concealing the mechanics of the conversion to maintain a desirable appearance.
2. Description of the Background
The aftermarket for performance and specialty auto parts provides consumers with the ability to customize their vehicle to suite their tastes and needs. Cars can be customized to improve performance, aesthetics, efficiency, emissions or other reasons and are often judged in shows and at racing events on these criteria. The increasing cost of fuel is generally of concern to all drivers. One way that manufacturers have improved the power, performance and efficiency of internal combustion engines is by replacing the mechanical carburetor system of mixing fuel and engine intake air with a fuel injection system. Fuel injection systems use electronically controlled fuel injectors to deliver a precisely metered amount of fuel to the engine at controlled intervals and provide significantly better control of the fuel/air mixture thereby increasing both performance and efficiency.
Although designs vary widely, all carburetors operate on the same design principals. Air is drawn into the engine via an air filter housing and then the carburetor by the pumping action of the pistons. As the air enters the top of the carburetor it passes a venturi or restriction in the throttle bore causing the air to speed up and resulting in a drop in total pressure. This pressure drop pulls fuel from a reservoir or float bowl through a jet and into the throttle bore where it is mixed with the intake air and distributed by the intake manifold and drawn into the cylinders via the cylinder intake ports.
Fuel injection fuel delivery systems replace the float bowl and jets of the carburetor with electronically controlled injectors. The injectors spray a fine mist of fuel from a high pressure fuel supply into the engine air under the timing and control of an electronic system. The position of the injectors in the system varies. Some systems place the injectors in the throttle body, referred to as single point fuel injection systems or throttle body fuel injection (TBI), while other systems incorporate the injectors into the intake manifold and inject the fuel spray directly into each cylinder intake port. Referred to as multi-port fuel injection, or tuned-port (TPI) fuel injection, these systems have a fuel injector for each cylinder and provide more accurate fuel metering and quicker response and provides greater engine control, but require an intake manifold and engine specifically designed for this purpose.
Most recently direct injection systems have been developed in which the injector delivers the fuel spray into the cylinder combustion chamber directly. Gasoline direct injection entails injection via a common rail fuel line directly into the combustion chamber of each cylinder, as opposed to conventional fuel injection that happens in the intake tract, or cylinder port.
Many car enthusiasts are particularly interested in racing and showing vintage vehicles that were originally built before the widespread implementation of fuel injected engines and which are thus powered by carbureted engines. Converting an older carbureted engine to a fuel injected system is challenging due to the need to incorporate the injectors, fuel pressure regulator, fuel supply rails and electronic control components into an engine that was not originally designed to have them, and to do so within a vehicle engine bay that was not designed to accommodate the additional parts. Conversion generally requires disassembly of a substantial portion of the engine including the air intake manifold provided by the original manufacturer. The primary function of the air intake manifold is to evenly distribute the combustion fuel/air mixture to each intake port in the cylinder heads. The intake manifold also serves as a mount for the air filter, carburetor or throttle body, and other components of the engine. Conversion entails removal of each of these components and replacement with a fuel injection system. This work is often beyond the skill or resources of vehicle owners.
Vehicle owners have a variety of commercial conversion kits available for purchase. Such kits are patched together from disparate and custom parts and, while generally functional, drastically change the “under-the-hood” and coachwork aesthetics of the vehicle and so are generally unsuitable for display in auto shows and judged competitions. Vintage car owners want their cars to appear true to their era, while being as technologically modern as possible. These homebuilt or kit systems also suffer from an inability to modify air flow and fuel delivery characteristics to match the needs of the particular engine once installed leading to poor engine performance and low efficiency. If a home built system does not perform well it must be removed and redesigned from the ground up, sometimes repeatedly, to match the fuel and air needs of the engine. In many vintage vehicles, conversion to a fuel injector system is altogether impossible given the geometry of various engine bays and other components.
It would be greatly advantageous to provide a carbureted-to-fuel injection conversion that does not also require replacement of significant engine components such as the intake manifold. It would be further advantageous to provide a carbureted-to-fuel injection conversion having tunable airflow characteristics, that is adaptable to the engine geometry of a variety of vintage vehicles and that conceals the fuel supply and other components of the system to preserve, to a large degree, the aesthetics of the engine.